1. Field of the Invention
The present invention relates to a fastener member for molding which is embedded in the surface of a cushion when an automotive seat cushion or office chair cushion is molded. The fastener member molded in the cushion is used to fix the upholstery material (such as cloth) covering the cushion.
2. Discussion of the Background
An automotive seat or office chair is usually made up of a cushion of foamed polyurethane or the like and an upholstery material covering it. According to conventional technology, the cushion has molded wires, and the upholstery is attached to the cushion by means of metal fixing members which engage the molded wires and the upholstery. This procedure is accomplished by the aid of an electric tool.
A new method utilizing insert molding has recently been proposed for the production of an automotive seat. This method involves the steps of inserting flat fastener tapes in the recesses of the mold, injecting a foaming resin into the mold, and expanding the resin such that the fastener tapes are integrally embedded in the surface of the cushion. The fastener tape has a large number of engaging elements on its top side and a large number of anchoring elements on its back side. The molded cushion, therefore, has the engaging elements bared on its surface. The cushion is finally covered with an upholstery material having elements capable of engagement with the engaging elements of the fastener tape.
The above-mentioned procedure needs a provision for preventing the foaming resin from entering the gap between the fastener tape and the recess of the mold in which it is fitted, because there is a possibility that the engaging elements are buried in the foamed resin that enters the gap.
This problem is solved by the use of a fastener member as shown in FIG. 9. The fastener member (A) is made up of a flat fastener tape (E), a steel strip (F), and a cover film (G). The flat fastener tape (E) has a large number of engaging elements (C) and anchoring elements (D) formed on both sides of its substrate. The steel strip (F), which is placed on the engaging elements (C), causes the fastener tape (E) to be attracted to the magnet (J) arranged in the recess of the mold. The cover film (G) covers the steel strip (F) and the engaging elements (C). The cover film (G) has its periphery bonded to the periphery of the flat fastener tape (E) by means of adhesion or heat sealing.
Prior to the molding operation, the fastener member (A) is fixed in position by the magnetic force exerted on the steel strip (F) by the magnet (J) arranged in the recess (K) of the mold. Subsequently, a foaming resin is injected into the mold so as to produce a cushion in which the anchoring elements are embedded. The cover film prevents the engaging elements from being buried in the foaming resin. After molding, the cover film (G) and the steel strip (F) are removed, so that the engaging elements (C) of the flat fastener are bared on the cushion.
Another fastener member of the molded-in type for the same purpose as mentioned above is disclosed in Japanese Patent Laid-open No. 64-9708/1989. It is a fastener tape having a groove on its entire periphery. It is fitted to the mold by the aid of the groove which is formed on the periphery of the recess in the mold, so that the fastener groove engages with the recess groove in the mold. Said prior art further discloses that the fastener tape has a flat rim outside the groove, and it seems that the fastener tape is fitted to the recess of the mold by the combination of the groove and the flat rim.
Another fastener member of molded-in type is disclosed in Japanese Utility Model Laid-open No. 3-58109/1991. It is a fastener tape having on its entire periphery a fitting member having a rectangular section. It has a disadvantage of being undesirably wide due to the fitting member. It has another disadvantage that the fitting member has to be formed separately from the flat fastener tape and then attached to the periphery of the flat fastener tape. This disadvantage leads to low productivity.
The above-mentioned method of attaching the upholstery to the cushion by the aid of molded wires and metal fixing members (so-called Hogring method) has the disadvantage of requiring a large number of metal fixing members and a great deal of labor. In addition, it poses a problem with safety and health e.g., wounds and tenosynovitis which results from using an electric tool for the metal fixing members. Another disadvantage is that the cushion after scrapping cannot be easily recycled because it contains metal parts such as wires and fixing members.
The fastener member shown in FIG. 9 has the disadvantage that it is necessary to remove the steel strip (F) and the fastener cover film (G) after molding. After removal, they are disposed of as waste. Another disadvantage is that the film (G) has to be completely removed with great care; even a small piece of film remaining on the engaging elements reduces the engaging force and aggravates the appearance. The removal of the film is troublesome and the removal of the steel strip (F) may injure the fingers.
The fastener member disclosed in Japanese Patent Laid-open No. 64-9708/1989 has the disadvantage of requiring a complex construction in both the fastener tape and the mold. The former has a groove on its periphery and the latter is provided with a grooved ridge which engages with the groove of the fastener tape. In addition, the groove increases the width of the fastener but has no engaging elements. This is undesirable especially in the case of narrow fasteners.